Sökning: "fossil"

Visar resultat 1 - 5 av 842 avhandlingar innehållade ordet fossil.

  1. 1. Biocarbon for fossil coal replacement

    Författare :Aekjuthon Phounglamcheik; Kentaro Umeki; Mašek Ondřej; Luleå tekniska universitet; []
    Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Biomass pyrolysis; charcoal; bio-oil recycling; CO2 utilization; reactivity; rotary drum; Energiteknik; Energy Engineering;

    Sammanfattning : This research aims to provide a full view of knowledge in charcoal production for fossil coal replacement. Charcoal from biomass is a promising material to replace fossil coal, which is using as heating source or reactant in the industrial sector. LÄS MER

  2. 2. Dating Divergence Times in Phylogenies

    Författare :Cajsa Lisa Anderson; Kåre Bremer; Katleen M. Pryer; Uppsala universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; systematic biology; divergence time; nonprametric rate smoothing; Bayesian; multidivtime; eudicots; Neoaves; monocots; dating; molecular clock; relaxed clock; age constraint; fossil; calibration; PATHd8; penalized likelihood; Biology; Biologi;

    Sammanfattning : This thesis concerns different aspects of dating divergence times in phylogenetic trees, using molecular data and multiple fossil age constraints.Datings of phylogenetically basal eudicots, monocots and modern birds (Neoaves) are presented. Large phylograms and multiple fossil constraints were used in all these studies. LÄS MER

  3. 3. Holocene Climate in Central and Southern Sweden : Quantitative Reconstructions from Fossil Data

    Författare :Karin Antonsson; Keith Bennett; Heikki Seppä; Andy Lotter; Uppsala universitet; []
    Nyckelord :Quaternary geology; pollen analysis; climate reconstructions; transfer functions; vegetation dynamics; Sweden; Kvartärgeologi;

    Sammanfattning : In quantitative palaeoecology modern species-environmental relationships can be statistically modelled, and recent development has made the calibration models more statistically robust. These models are used to transform fossil assemblages to quantitative estimates of past environmental conditions. LÄS MER

  4. 4. Evolutionary Progression of the Iconic Australasian Kangaroos, Rat-Kangaroos, and their Fossil Relatives (Marsupialia: Macropodiformes)

    Författare :Wendy den Boer; Benjamin Kear; Christine Janis; Uppsala universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; macropodiforms; kangaroos; rat-kangaroos; fossil ancestors; post-cranial; eco-morphology; systematic; phylogeny; Earth Science with specialization in Historical Geology and Palaeontology; Geovetenskap med inriktning mot historisk geologi och paleontologi;

    Sammanfattning : The exceptionally diverse macropodiform’s (kangaroos, rat-kangaroos and their fossil allies) currently have a fossil record that spans from the late Oligocene to the Holocene with an Australasian widespread fossil occurence. The origins of the macropodiforms are believed to have been during the Eocene possibly having split from the Phalangeridae. LÄS MER

  5. 5. Environmental records of carbonaceous fly-ash particles from fossil-fuel combustion

    Författare :Maria Wik; Lars Ericson; Umeå universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Carbonaceous particles; soot; anthropogenic particles; oil and coal combustion; fossil fuel combustion; lake sediments; lake acidification; forest soils; historical monitoring;

    Sammanfattning : Fossil fuel combustion produces fly-ash particles that are released into the atmosphere and deposited in the environment. A particularly characteristic kind of fly-ash is spheroidal carbonaceous particles. They are composed of an amorphous carbon matrix in which other elements are dispersed. LÄS MER